In any industrial installation utilizing rotating machines or other machinery having continuously moving parts it is often desirable and sometimes virtually essential to develop some technique for effective visual inspection of moving parts of the equipment for setup purposes and for repair and maintenance. That is, inspection of the machinery when shut down may be inadequate to reveal sources of malfunction, whereas an effective visual inspection with the machinery actually in operation may promptly disclose sources of malfunction that could not be determined with the equipment stationary. On the other hand, effective visual inspection of rapidly rotating or moving parts becomes virtually impossible unless maintenance personnel are provided with visual aids that can be synchronized with the high speed movements of the machinery.
In circumstances of this kind, the most effective visual aid for maintenance purposes is often a stroboscope that can be synchronized to the rate of movement of any individual part of the machinery to effectively "arrest" any such part, on a visual basis, and thus allow for effective inspection without shutting down the machinery. But industrial stroboscope equipment suitable for troubleshooting use is usually rather expensive and often requires an external power supply connection that may not be conveniently available in a given industrial installation. Furthermore, conventional stroboscope apparatus is often heavy and bulky so that it is difficult to maneuver into a good viewing position for a specific part of the industrial machinery and may be awkward and tiring for the maintenance or setup mechanic if protracted inspection becomes necessary. Thus, there is a definite need for an inexpensive stroboscope, operable over a broad frequency range to match up with varying speeds for different moving parts in industrial equipment, a stroboscope that is relatively compact and highly portable in nature and that requires no external power line connection.
The conventional automotive timing light, used for timing adjustments of the individual cylinders of an automotive engine, has many of the attributes that are desirable in a stroboscope useful for industrial troubleshooting operations, such as those noted above. Thus, the conventional hand-held automotive timing light affords a light source with adequate output for industrial maintenance and is capable of operation over a relatively broad frequency range. But the automotive timing light has no power source; power is obtained by connection to the battery of the automotive vehicle through a power cord with alligator clamps adapted for connection to the battery terminals. Furthermore, the conventional automotive timing light has no provision for independent frequency control; it includes an inductive pickup clamp that fits around the power lead to the spark plug of the cylinder under adjustment so that the light operates at the actual firing rate for that cylinder. Thus, by itself the conventional automotive timing light cannot be used for the industrial troubleshooting operations referred to above.